This invention relates to a simple method of minimizing the gap between the barrel rear, usually a forcing cone, and the front face of the cylinder of a revolver firearm, which is independent of manufacturing tolerances. It is known that revolvers and other firearms with a cylinder for firing ammunition have a gap between the forcing cone and the cylinder, which cannot be avoided because of manufacturing tolerances, and therefore cannot be held to a minimum in mass produced firearms. The maximum allowable gap size is about 0.3 mm although a maximum of about 0.22 mm is preferred. There is a pressure drop at this gap when a cartridge is fired and lead particles, which can be hazardous, frequently emanate under great pressure. The bottom of the top strap may also suffer flame cutting. Manuhrin, which manufactures expensive revolvers, holds the gap to a minimum by expensive hand fittings on their target revolvers.
Nagant attempted to solve this problem by camming the cylinder forward during firing, so that no gap existed between the cylinder face and the cone. This system was relatively complicated.